Field of the Disclosure
The present invention relates to a liquid crystal display device, and more particularly, to an array substrate capable of preventing a defect caused by a movement of a column spacer due to an external environment and a liquid crystal display device including the same.
Description of the Related Art
A liquid crystal display device has a high contrast ratio and is suitable for displaying a dynamic image with low power consumption, and, thus, it has been applied to various devices such as notebook computers, monitors, and TVs. Liquid crystal molecules, with a thin and long structure, have optical anisotropy by which there is directionality in their alignment. There is a polarization effect when an electric field is applied to the liquid crystal molecules and the molecules change in alignment direction. The liquid crystal display device displays an image using optical anisotropy and polarization of the liquid crystal molecules.
Generally, a liquid crystal display device includes a liquid crystal panel formed by interposing and bonding a liquid crystal layer between a first substrates and a second substrate, and electrodes are respectively formed inside each of the first substrate and the second substrate. An alignment direction of liquid crystal molecules is changed by an electric field applied to the electrodes, resulting in a change in light transmittance.
Such a change in light transmittance of the liquid crystal panel allows a light supplied from a backlight provided at the rear of the liquid crystal panel to be modulated. Color can be presented when the light supplied from the backlight passes through a color filter formed on one of the first or second substrates and is displayed in the form of an image.
Typically, a liquid crystal display device manufacturing process is divided into a substrate manufacturing process for forming each of an array substrate and a color filter substrate, a cell process for completing a liquid crystal panel, and a module process for integrating the liquid crystal panel and a backlight.
Particularly, in the substrate manufacturing process, a thin film deposition process, a photo-lithography process, and an etching process are repeated many times to form an array layer and a color filter layer on each substrate. An alignment film is formed on at least one of the substrates to orient the liquid crystal molecules. In the cell process, a seal pattern for bonding is formed on any one of an array substrate and a color filter substrate and the two substrates are bonded to each other with a liquid crystal layer interposed in between so as to complete a liquid crystal panel. In the module process, the completed liquid crystal panel is provided with a polarization plate and a driving circuit and is integrated with a backlight, to complete a liquid crystal display device.
Between the array substrate and the color filter substrate, a spacer is configured to maintain a uniform distance between the two substrates. The spacer is classified into a ball spacer or a column spacer depending on a shape and an arrangement method. The ball spacer is formed to be scattered on the array substrate or the color filter substrate, and the column spacer is formed by patterning on the array substrate or the color filter substrate.
In recent years, the column spacer which can be formed into a desired shape at a specific position has been widely used. The column spacer is typically formed on the color filter substrate to which relatively fewer processes are performed. However, when an external force is applied, the column spacer is moved and an alignment film is damaged, thereby causing a defect to the liquid crystal panel.